Public Water System Design and Implementation in Texas

Public water system design in Texas follows TCEQ's Rules and Regulations for Public Water Systems, 30 TAC Chapter 290, Subchapter D. Those rules size the system per connection (0.6 gpm of well capacity and 200 gallons of storage for most groundwater systems), set a 35 psi floor in the mains, control how wells are sited and sealed, and require written TCEQ approval of sealed plans before construction starts.

What rules govern public water system design in Texas?

TCEQ's 30 TAC Chapter 290, Public Drinking Water, governs it. Subchapter D (§290.38 to §290.47) holds the design and operating rules. Subchapter F (§290.101 to §290.122) covers drinking water quality, monitoring and reporting.

The rules apply to a public water system: at least 15 service connections, or at least 25 people served at least 60 days a year (§290.38). A community system has the potential to serve 15 residential connections year-round, so a subdivision planned for 15 or more homes on its own wells can count before they are built.

Who designs a water supply system, and how does a public owner contract for it?

A Texas licensed professional engineer designs it; TCEQ only reviews (§290.39(d)(3)(A)). TCEQ considers only plans prepared under a licensed engineer's direction and sealed, signed and dated under Texas Board of Professional Engineers and Land Surveyors rules (§290.39(d)(1)).

When the owner is a district, authority, city, county or publicly owned utility, the Professional Services Procurement Act, Texas Government Code Chapter 2254, governs the contract: the owner first selects the most highly qualified engineer on demonstrated competence and qualifications, then negotiates a fair and reasonable price (§2254.004).

When does TCEQ have to approve the plans?

Before you build a new system, and before any significant change to an existing one (§290.39(h)(1) and (j)). Submit detailed plans at least 30 days before you need comments, with no promise of action in that time (§290.39(d)(2)).

TCEQ's public water system plan review page lists the package: a cover letter, the TCEQ-10233 submittal form, an engineering report, and sealed plans and specifications. A new system adds a Core Data Form, financial forms, requests for service and, for a community system, a business plan.

This matters most to developers and builders. In a city's extraterritorial jurisdiction, or within half a mile of a district's boundary or another provider's certificated service area, you first apply in writing for service from that provider and meet its application requirements (§290.39(c)(1)). Your own system comes next only if service is denied or its cost estimate is not feasible (§290.39(c)(3)).

How much capacity does TCEQ require per connection?

For a groundwater community system with 50 to 250 connections, 30 TAC §290.45 requires, per connection, 0.6 gpm of well capacity, 200 gallons of total storage, service pumps totaling 2.0 gpm, and 100 gallons of elevated storage or 20 gallons of pressure tank. Other tiers:

• Under 50 connections with no ground storage: 1.5 gpm of well capacity and 50 gallons of pressure tank per connection.
• Over 250 connections: at least two wells sharing the 0.6 gpm, and service pumps at 2.0 gpm per connection or at least 1,000 gpm that meets peak hourly demand with the largest pump out, whichever is less.
• Over 2,500 connections: elevated storage of 100 gallons per connection.
• Surface water: treatment plant capacity of 0.6 gpm per connection.

These are minimums only (§290.45(a)(1)). Alternatives can be requested with 36 consecutive months of demand data (§290.45(g)).

What pressure, pipe and separation rules apply to distribution mains?

Design for 35 psi at all points at 1.5 gpm per connection, and 20 psi under combined fire and drinking water flow if the system will fight fire (30 TAC §290.44(d)). §290.44 also sets pipe rules:

• Pipe and fittings certified to ANSI/NSF Standard 61.
• Top of pipe below the frost line and never less than 24 inches deep.
• No new line under 2 inches, sized up with the customers served.
• Nine feet in all directions from wastewater collection facilities (§290.44(e)). Where that cannot be met, a new waterline paralleling a new sewer sits at least two feet above and four feet away, with the sewer in 150 psi pressure-rated pipe.

Chapter 290 sets residential fire flow (250 gpm for two hours at 20 psi) only for certain cities or by city ordinance (§290.46(x) and (y)); otherwise, get it from the local fire authority early, because it often sets main size. A hydraulic model proves the pressure, and EPANET water modeling is a common way to build one. For a subdivision, these checks are most of the work in water distribution design for Texas land development.

What does TCEQ require for well design and drilling?

A protected site, a sealed annulus and approved test results. 30 TAC §290.41(c) requires:

• At least 50 feet from tile or concrete sewers and septic tanks, 150 feet from drainfields, 300 feet from sewage pumping stations, and 500 feet from sewage treatment plants.
• A recorded sanitary control easement over the land within 150 feet of the well, or an approved substitute.
• Casing at least 18 inches above the pump room floor or natural ground.
• Neat cement pressure-grouted in the annulus from the top of the shallowest formation to be developed up to the surface.
• Three successive daily raw water samples free of coliform after disinfection.
• A complete physical and chemical analysis after 36 hours of continuous pumping at the design rate.

The driller's log, cementing certificate, test results and easements go to TCEQ for approval before the well serves anyone.

What treatment and testing come before water reaches customers?

Disinfection always, and more treatment if the water analysis calls for it. All groundwater is disinfected before distribution, TCEQ may require 4-log virus treatment, and chemicals must meet ANSI/NSF Standard 60 (§290.42). The mains must hold at least 0.2 mg/L free chlorine or 0.5 mg/L chloramine (§290.110).

New mains must meet AWWA leakage limits (§290.44(a)(5)), then are disinfected under AWWA C651 and sampled at least once per 1,000 feet (§290.44(f)). At completion, the engineer or owner tells TCEQ in writing that the work substantially matches the approved plans (§290.39(h)). A groundwater system of 250 connections or fewer then needs a Class D or higher operator (§290.46(e)).

Where are TCEQ's sanitary sewer and wastewater design criteria?

In a different chapter. Sewer and treatment plant design falls under 30 TAC Chapter 217, Design Criteria for Domestic Wastewater Systems. Conventional collection systems are in Subchapter C (§217.51 to §217.71). The chapters meet at crossings: a new waterline crossing under a wastewater main follows §217.53(d), as §290.44(e) directs.

Is your project ready for a TCEQ submittal?

Yes to all six means ready. Fix any no first.

1. Do you know the buildout connection count and its §290.45 tier?
2. Have you requested service in writing from every nearby provider the rule names?
3. Is a sanitary control easement recorded for every well?
4. Does the model show 35 psi at 1.5 gpm per connection, and 20 psi under fire flow?
5. Does every waterline keep nine feet from sewers, or meet the closer-spacing criteria?
6. Are the report, plans and specifications sealed, with every TCEQ form attached?

Limits: this is general education on Chapter 290 as published in October 2026. Your site and TCEQ's reviewer decide what applies, and nothing here predicts a review outcome or timeline.

Frequently asked questions

What is 30 TAC Chapter 290?

The Public Drinking Water chapter of the Texas Administrative Code. TCEQ administers it, and Subchapter D holds the design rules.

Does Chapter 290 cover sewer design?

No. TCEQ's sewer design criteria are in 30 TAC Chapter 217.

I'm a developer planning a 120-lot Texas subdivision on its own wells, outside any city's ETJ. What does TCEQ require before I build the water system?

First, request service in writing from any district or provider whose boundary or certificated area is within half a mile. If service is denied or its cost estimate is not feasible, submit the report, sealed plans, new-system forms and a business plan, then wait for written approval. At 120 connections, the 50 to 250 tier means 72 gpm of well capacity, 24,000 gallons of storage, 240 gpm of service pumps, and 12,000 gallons elevated or a 2,400-gallon pressure tank.

I run the water utility for a Texas city on groundwater with 400 connections, and a developer wants a 60-lot phase. Do we need TCEQ plan review for the line extension?

Yes, unless the city reviews it in house. Sixty is a 15% increase, and distribution changes over 10% of connections need plans (§290.39(j)). The exception, open to a political subdivision: a licensed engineer it employs, independent of the designers, certifies in writing that the extension meets §290.44 and will not violate §290.45, and that certification goes with the notice (§290.39(j)(3)). Either way, check 460 connections: at least two wells totaling 276 gpm, and 92,000 gallons of storage.

Related resources

• New Water Main Disinfection and Test Water Discharge: How to Coordinate AWWA Standards with TCEQ Rules
• How to Conduct a Fire Flow Analysis for a Texas Development or Subdivision
• Water Storage and Pressure Zone Design for McKinney's Rolling Terrain: Engineering for Collin County Topography
• CCN Territory Disputes in Collin County: What to Check Before Land Crosses a Water Provider Boundary

Planning a new public water system or an expansion in Texas?

We check the connection count, capacity tier, service requests and well data against Chapter 290 before the package goes to TCEQ.

Modern Engineering Solutions is headquartered in McKinney, Texas, with 525+ projects completed. Call (214) 833-6748.

Talk with an engineer about your water system